They're pretty cool to see, super long so it really jumps out at you when you've got one in hand.
Mine are US Cartridge cases loaded by a shell company from California who's name escapes me right at the moment for some reason. I got two different ones from the guy.
Got any unusual paper shells to trade? I might be persuaded.....
It took me 10 years of looking to find one after finding out such a thing existed.